Generally, the answer is no. If an ex-spouse who is paying child support has another child with his or her new spouse, the amount of child support being paid should not be affected. Child support in North Carolina is based on the combined income of the respective parties, the number of overnights spent with each parent, expenses for any special needs of the child, and any pre-existing child support obligations.
The only recourse for a spouse who wants to lower his or her child support obligation for a child from his or her first marriage would be through a motion to the court to deviate from the child support guidelines. In order to deviate from the guidelines the spouse would have to show that the current child support obligation was unfairly burdensome or unjust in some way.